Macro and micro nutrient limitation of microbial productivity in oligotrophic subtropical Atlantic waters

2008 ◽  
Vol 5 (2) ◽  
pp. 135 ◽  
Author(s):  
Joanna L. Dixon
Keyword(s):  
Primary Production ◽  
Bacterial Production ◽  
Heterotrophic Bacteria ◽  
Total Carbon ◽  
North East ◽  
Incubation Experiments ◽  
Subtropical Oceans ◽  
Marine Primary Production

Environmental context. The subtropical oceans comprise ~70% of the world’s ocean surface and profoundly affect global biogeochemistry and climate. They are characteristically low-nutrient regions, but, owing to their large extent and often rapid nutrient turnover, may contribute to greater than 30% of the total marine primary production. However, there remains long-standing uncertainty as to what individual or combination of resources, e.g. macro (N, P) and micro (trace metals) nutrients, limit or co-limit marine productivity and thus total carbon fixation in these spatially dominant gyre systems. Abstract. The subtropical oceans are characteristically low-nutrient low-chlorophyll regions, but owing to their geographical dominance and rapid nutrient cycling may contribute >30% of the total marine primary production. The present study investigates the addition of P, Fe, Co and Zn on rates of primary production and heterotrophic bacterial production, through a combination of mesoscale in situ (P, and P + Fe) and in vitro (Co or Zn) bioassay incubation experiments. Results from the bioassay incubation experiments suggest that primary production and chlorophyll a biomass are limited by N and P in this oligotrophic region. However, both were increased further after addition of trace metal micronutrients in the order Fe + Zn ≥ Fe + Co > Fe ≈ Co. In contrast, rates of heterotrophic bacterial production did not appear to be P, or significantly, P + Fe limited, although in situ rates did increase during the first 12 h of mesoscale P fertilisation (which were not mirrored in the mesoscale P + Fe addition). The addition of Co to unfertilised waters increased heterotrophic bacterial production and the numbers of heterotrophic bacteria, Prochlorococcus spp. and Synechococcus spp., suggesting Co limitation. Prochlorococcus spp. were the most abundant autotrophs. The highest increases in both heterotrophic and autotrophic carbon assimilation were shown after in vitro addition of either Co or Zn to mesoscale enriched P + Fe waters, suggesting multiple limitation of microbial growth rates in the subtropical oligotrophic north-east Atlantic.

scholarly journals Empirical Leucine-to-Carbon Conversion Factors for Estimating Heterotrophic Bacterial Production: Seasonality and Predictability in a Temperate Coastal Ecosystem

2009 ◽  
Vol 75 (10) ◽  
pp. 3216-3221 ◽  
Author(s):  
Alejandra Calvo-D�az ◽  
Xos� Anxelu G. Mor�n
Keyword(s):  
Protein Synthesis ◽  
Bacterial Production ◽  
Heterotrophic Bacteria ◽  
Spatiotemporal Variability ◽  
Leucine Incorporation ◽  
Carbon Conversion ◽  
Conversion Factors ◽  
Production Studies ◽  
Favorable Conditions

ABSTRACT Leucine-to-carbon conversion factors (CFs) are needed for converting substrate incorporation into biomass production of heterotrophic bacteria. During 2006 we performed 20 dilution experiments for determining the spatiotemporal variability of empirical CFs in temperate Atlantic coastal waters. Values (0.49 to 1.92 kg C mol Leu−1) showed maxima in autumn to early winter and minima in summer. Spatially averaged CFs were significantly negatively correlated with in situ leucine incorporation rates (r = −0.91) and positively correlated with phosphate concentrations (r = 0.76). These relationships, together with a strong positive covariation between cell-specific leucine incorporation rates and carbon contents (r = 0.85), were interpreted as a strategy to maximize survival through protein synthesis and low growth rates under nutrient limitation (low CFs) until favorable conditions stimulate cell division relative to protein synthesis (high CFs). A multiple regression with in situ leucine incorporation rates and cellular carbon contents explained 96% of CF variance in our ecosystem, suggesting their potential prediction from more easily measurable routine variables. The use of the theoretical CF of 1.55 kg C mol Leu−1 would have resulted in a serious overestimation (73%) of annual bacterial production rates. Our results emphasize the need for considering the temporal scale in CFs for bacterial production studies.

Studies in situ of the primary production of an area of inshore antarctic sea

1969 ◽  
Vol 49 (2) ◽  
pp. 393-405 ◽  
Author(s):  
A. J. Horne ◽  
G. E. Fogg ◽  
D. J. Eagle
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
High Light ◽  
Total Carbon ◽  
The South ◽  
Orkney Islands ◽  
In Situ Techniques ◽  
Light Intensities ◽  
South Orkney Islands

The primary productivity of an area of inshore sea in the South Orkney Islands was measured using in situ techniques in two consecutive seasons. Liberation of extracellular products of photosynthesis occurred, accounting for about 1 % of the total carbon fixed at the depth of maximum photosynthesis but rising to 38 % or more when photosynthesis was inhibited at high light intensities.

Determination and localisation of in situ substrate uptake by anaerobic wastewater treatment granular biofilms

2007 ◽  
Vol 55 (8-9) ◽  
pp. 369-376 ◽  
Author(s):  
G. Collins ◽  
T. Mahony ◽  
A.-M. Enright ◽  
A. Gieseke ◽  
D. de Beer ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
In Situ Hybridisation ◽  
Substrate Uptake ◽  
Methanogenic Activity ◽  
Anaerobic Wastewater Treatment ◽  
Complementary Approach ◽  
Incubation Experiments ◽  
Testing And Measurement

Radiotracer incubation experiments and beta microimaging, along with fluorescent in situ hybridisation (FISH), are proposed as a complementary approach to specific methanogenic activity testing and measurement of in vitro substrate utilisation rates to understand better the ecophysiology of anaerobic granular biofilms from wastewater treatment reactors.

scholarly journals Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

2016 ◽  
Vol 13 (11) ◽  
pp. 3187-3202 ◽  
Author(s):  
France Van Wambeke ◽  
Ulrike Pfreundt ◽  
Aude Barani ◽  
Hugo Berthelot ◽  
Thierry Moutin ◽  
...  
Keyword(s):  
Primary Production ◽  
Bacterial Growth ◽  
N2 Fixation ◽  
Bacterial Production ◽  
Heterotrophic Bacteria ◽  
New Caledonia ◽  
Gross Primary Production ◽  
Growth Efficiency ◽  
Bacterial Growth Efficiency ◽  
Second Phase

Abstract. Studies investigating the fate of diazotrophs through the microbial food web are lacking, although N2 fixation can fuel up to 50 % of new production in some oligotrophic oceans. In particular, the role played by heterotrophic prokaryotes in this transfer is largely unknown. In the frame of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) experiment, three replicate large-volume (∼ 50 m3) mesocosms were deployed for 23 days in the new Caledonia lagoon and were intentionally fertilized on day 4 with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between heterotrophic bacterial production (BP) and N2 fixation or primary production, determined bacterial growth efficiency and established carbon budgets. BP was statistically higher during the second phase of the experiment (P2: days 15–23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5–14). Phosphatase alkaline activity increased drastically during the second phase of the experiment, showing adaptations of microbial populations after utilization of the added DIP. Notably, among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget (27–43 %), was notably higher than generally cited for oligotrophic environments and discussed in links with the presence of abundant species of bacteria expressing proteorhodopsin. The main fates of gross primary production (particulate + dissolved) were respiration (67 %) and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but was slightly correlated, and only during P2 phase, with N2 fixation rates. Heterotrophic bacterial production was strongly stimulated after mineral N enrichment experiments, suggesting N-limitation of heterotrophic bacteria across the experiment. N2 fixation rates corresponded to 17–37 % of the nitrogen demand of heterotrophic bacteria. Our results suggest that most of the diazotroph-derived nitrogen fuelled the heterotrophic bacterial community through indirect processes generating dissolved organic matter and detritus, like mortality, lysis and grazing of both diazotrophs and non-diazotrophs.

scholarly journals Decrease in the Autotrophic-to-Heterotrophic Biomass Ratio of Picoplankton in Oligotrophic Marine Waters Due to Bottle Enclosure

2011 ◽  
Vol 77 (16) ◽  
pp. 5739-5746 ◽  
Author(s):  
Alejandra Calvo-Díaz ◽  
Laura Díaz-Pérez ◽  
Luis Ángel Suárez ◽  
Xosé Anxelu G. Morán ◽  
Eva Teira ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Bacterial Respiration ◽  
Content Type ◽  
The North ◽  
Incubation Experiments ◽  
Biomass Ratio ◽  
Lagrangian Study ◽  
Biased Estimates ◽  
North And South

ABSTRACTWe investigated the effects of bottle enclosure on autotrophic and heterotrophic picoplankton in North and South subtropical Atlantic oligotrophic waters, where the biomass and metabolism of the microbial community are dominated by the picoplankton size class. We measured changes in both autotrophic (Prochlorococcus,Synechococcus, and picoeukaryotes) and heterotrophic picoplankton biomass during three time series experiments and in 16 endpoint experiments over 24 h in light and dark treatments. Our results showed a divergent effect of bottle incubation on the autotrophic and heterotrophic components of the picoplankton community. The biomass of picophytoplankton showed, on average, a >50% decrease, mostly affecting the picoeukaryotes and, to a lesser extent,Prochlorococcus. In contrast, the biomass of heterotrophic bacteria remained constant or increased during the incubations. We also sampled 10 stations during a Lagrangian study in the North Atlantic subtropical gyre, which enabled us to compare the observed changes in the auto- to heterotrophic picoplankton biomass ratio (AB:HB ratio) inside the incubation bottles with those taking placein situ. While the AB:HB ratioin situremained fairly constant during the Lagrangian study, it decreased significantly during the 24 h of incubation experiments. Thus, the rapid biomass changes observed in the incubations are artifacts resulting from bottle confinement and do not take place in natural conditions. Our results suggest that short (<1 day) bottle incubations in oligotrophic waters may lead to biased estimates of the microbial metabolic balance by underestimating primary production and/or overestimating bacterial respiration.

scholarly journals Variations in triple isotope composition of dissolved oxygen and primary production in a subtropical reservoir

2016 ◽  
Author(s):  
Hana Jurikova ◽  
Tania Guha ◽  
Osamu Abe ◽  
Fuh-Kwo Shiah ◽  
Chung-Ho Wang ◽  
...  
Keyword(s):  
Primary Production ◽  
Isotope Composition ◽  
Environmental Parameters ◽  
Order Of Magnitude ◽  
Lakes And Reservoirs ◽  
Net To Gross ◽  
Feitsui Reservoir ◽  
Incubation Method

Abstract. Lakes and reservoirs play an important role in the carbon cycle, and therefore, monitoring their metabolic rates is essential. The triple oxygen isotope anomaly of dissolved O2 [17Δ = ln(1+δ17O) − 0.518×ln(1+δ18O)] offers a new, in situ, perspective on primary production, but is yet to be evaluated in freshwater systems. We investigated the 17Δ together with oxygen-argon ratio (δO2/Ar) in the subtropical Feitsui Reservoir in Taiwan from June 2014 to July 2015. Here, we present the seasonal variations in 17Δ, GP (gross production), NP (net production) and the NP/GP (net to gross ratio) in association with environmental parameters measured. The 17Δ varied with depth and season, with values ranging between 19 and 186 per meg. The 17Δ GP rates were lower from April to September averaging 215±93 mg C m−2 d−1 and higher from October to January averaging 523±66 mg C m−2 d−1. The estimated average annual 17Δ GP was 104 g C m−2 year−1 and the average annual NP was 22 g C m−2 year−1. Overall, the NP/ GP varied slightly between 0.02 and 0.36 and the reservoir was net autotrophic in the mixed layer. Comparisons between 17Δ GP rates and the production rates estimated by in vitro 14C bottle incubation method (14C GP) were consistent on the same order of magnitude, with the 17Δ GP/14C GP ratio of 1±0.8 throughout the study. Although typhoon occurrences were scarce, higher than average 17Δ values and 17Δ GP rates were recorded after typhoon events.

Primary production in lakes Huron and Michigan: in vitro and in situ comparisons

1988 ◽  
Vol 10 (6) ◽  
pp. 1273-1283 ◽  
Author(s):  
Gary L. Fahnenstiel ◽  
Hunter J. Carrick
Keyword(s):  
Primary Production

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

1996 ◽  
Vol 54 ◽  
pp. 32-33
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris
Keyword(s):  
Alkaline Phosphatase ◽  
Room Temperature ◽  
Uncoupling Protein ◽  
Ppar Gamma ◽  
Nuclear Hormone Receptor ◽  
Full Length ◽  
Northern Analysis ◽  
Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

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